Determining impact induced damage by lamb wave mode extracted by EMD method

• In this paper, a method to diagnose structural impact damage based on AE is presented.
• S0 mode lamb waves can be used as the characteristic signal of impact damage.
• EMD was used to obtain the characteristic signal from impact AE.
• This method relative to other diagnostic methods has advantages in real time.

Structures with composite materials in daily use are subjected to impact. Determining if the material is damaged is an important aspect of structural health monitoring of composites. In this paper, a method to determine structural damage as a result of impact and localize the position of the damage based on lamb wave mode is presented. First, the paper analyses the characteristics of lamb wave mode generated by force loading on the plate. These results are validated based on the analysis of experimental results. From the results, it can be concluded that S0 mode lamb waves were generated by damage of the plate structure and it can be used as the characteristic signal of damage. Then, empirical mode decomposition (EMD) is utilized to decompose to the Intrinsic Mode Functions (IMF) of S0 mode inside the emission signals of complex acoustics to realize if damage occurs and localize the position of impact damage on the composite material plate.